Electro-acoustic generator adapted to produce low frequency signals transformable into musical sounds by means of any amplifiers



May 30, 1967 c. MARTIN 3,322,876

ELECTRO-ACOUSTIC GENERATOR ADAPTED TO PRODUCE LOW FREQUENCY SIGNALSTRANSFORMABLE INTO MUSICAL SOUNDS BY MEANS OF ANY AMPLIFIERS Filed Feb.20, 1964 United States Patent M 3,322,876 ELECTRO-ACOUSTIC GENERATORADAPTED TO PRODUCE LOW FREQUENCY SIGNALS TRANS- FORMABLE INTO MUSICALSOUNDS BY MEANS OF ANY AMPLIFIERS Constant Martin, 36 Ave. deSaint-Cloud, Versailles, France Filed Feb. 20, 1964, Ser. No. 346,241Claims priority, application France Feb. 26, 1963, 925,962, Patent1,357,713 4 Claims. (Cl. 84-1.15)

My invention has for its object an electro acoustic generator adapted toproduce low frequency signals transformable into musical sounds by meansof any amplifier.

My improved arrangement includes chiefly at least one movable elasticprojection adapted to move over a predetermined path and associated withmembers adapted to vibrate, each time they meet said movable elasticprojection and are shifted thereby out of an inoperative position by thethrust exerted on the member considered by said elastic projection, saidoperation being immediately followed by a release.

My invention includes furthermore electric collectors secured inproximity with the vibratory members and translating the vibratorymovements of the latter into electric currents of a reduced intensity.

The vibratory members may be of any nature and shape depending on theparticular requirements of each embodiment and they may assume the shapeof rods of any desired cross-section, said rods being rectilinear orcurvilinear or else I may resort to vibratory strings or to plates orvarious articles adapted to vibrate under the action of the transientthrust exerted by an elastic projection. Such vibratory members arepreferably made of magnetic material in the case of electromagneticcollectors and their number may vary according to the embodimentconsidered.

The elastic projection or projections forming part of my improvedarrangement may assume more particularly a circular movement so that theend of the projection may move along a circular line, but its path mayas well assume the shape of an ellipse or any other suitable closedcurve.

The drive of the projections may be ensured by any suitable means,whether directly or otherwise, or else they may be shifted by hand.

My improved arrangement may be modified in various manners and leads tovarious applications. It is more particularly adapted to be associatedwith an acoustic amplifier or system of amplifiers whereby the weakmodulaited currents produced by the collectors, are raised to a suitableamplitude so that they may actuate loudspeakers and produce thus musicalsounds or else they may act on the modulating circuits of a remotetransmission station or remote control station or an acoustic recordingapparatus. v 7

Other advantages and features of my invention will appear from thereading of the following description of an embodiment disclosed by wayof a mere indication and by no means in a limiting sense.

Said embodiment is illustrated in the accompanying drawings, the singlefigure of which is an exploded perspective view of said embodiment whichis constituted chiefly by the following parts:

An electric motor 1, associated with speed reducing means, and the shaftof which is adapted to revolve at a low speed, said motor being securedto the vertical flange of a supportingmember 2 which is Ushaped and theopposite flange of which is lined by a preferably metallic plate 3. Theshaft 4 of the mot-or 1 extends through the space separating the twoflanges of the sup- 3,322,876 Patented May 30, 1967 porting member 2 andits terminal section engages a perforation 5 formed in the plate 3. Tworectilinear rods of a suitable size 6, 7, 8 are locked each at one endby means of cooperating screws 9, 10 and 11 in the correspondingperforations 12, 13 and 14 formed in the flange of the supporting member2 associated with the plate 3 and in said plate, said perforations beingdistributed over a circumference of which the center registers with thefirst mentioned perforation 5.

A projection 18 constituted by a wire or a flat preferably metallicmember, acting as a spring, is rigidly secured to the shaft 4 controlledby the motor through the agency of an intermediate member 15 and of thesecuring screws 16 and 17. The length of the elastic projection orfinger 18 is such that its free end is adapted to meet in succession therods 6, 7 and 8 during the rotation of the shaft 4.

The relative arrangement of the'rods 6, 7 and 8 and of the elasticprojection 18 and the shape given to the end of the projection are suchthat, when said end of the projection engages a rod, it causes thevibration of the latter.

The rods 6, 7 and 8 are made of a magnetic metal although this is notesesntial if the collectors described hereinafter, are not constitutedby electro-magnetic collectors.

A plate 19 which, for sake of clarity of the drawing, is illustrated asshifted away from the upper section of the plate 3 is, in practice,secured to the latter by securing means illustrated at 20 and 21. On theother hand, said plate 19 carries three magnetized bars 22, 23 and 24 inperforations of the plate 19 in which they are suitably locked by thecorresponding screws 28, 29 and 30.

The lower end of the magnetized bar 22 is surrounded by a winding 25 andis located immediately above the rod 6 and at a short distance withreference to the latter.

Similarly, the lower ends of the bars 23 and 24, are surroundedrespectively by the winding 26 and by the winding 27 and are locatedimmediately above and at a short distance from the corresponding rods 7and 8 respectively,

A member 31 which is rigidly secured to the driving shaft 4, carries astud 32 terminating with an en-dpiece of an insulating material 33adapted to engage the elastic section of an electric switch constitutedby the contact blades 34 and 36 carried respectively by the insulatingsupports 35 and 37.

The electric connections between the motor 1, the contact-making blades34 and 36, the switch 40 and the terminals 41 and 42 of a suitablysupply of current, are executed in conformity with the drawing.

Lastly the windings 25, 26 and 27 are inserted in series and connectedwith the input of an amplifier 38 followed by a loud-speaker 39.

In the example illustrated, the windings of the collectors are insertedin series but it is possible also to insert them in parallel or inaccordance with any other suitable arrangement.

Similarly, the collectors of the present example are equal in numberwith the vibrating members, but it is possible to provide a number ofcollectors which is smaller than that of the vibrating members or even asingle collector may serve for the whole system of vibratory members.

The operation of the arrangement disclosed is as follows:

In the position illustrated, the terminal section 33 of the stud 32engages the blade 34 of which the end is spaced thus with reference tothe blade 36, the result of which is that the motor 1 is not connectedacross the terminals 41 and 42 of the supply of current.

If the switch 40 is then closed transiently, the motor is fed and theshaft 4 revolves and carries along in its rotation on the one hand, theelastic projection 18 and on the other hand, the stud 32 the end 33 ofwhich releases the blade 34 which engages now the blade 36 and closesthus the circuit feeding the motor throughout the duration of a completerevolution.

During said revolution, the end of the elastic projection 18 engages therod 6 and shifts it consequently out of its inoperative position and byreason of the elasticity of said rod and of that of the projection 18,the latter releases suddenly the rod which starts vibrating; the elasticprojection continuing its rotary movement, acts now in succession on therods 7 and 8 so as to produce vibrations similar to those produced byaction on the rod 6.

The vibrations of the rods 6, 7 and 8 produce in the windings 25, 26 and27, induced currents which are amplified by the amplifier 38 and aretranslated into musical sounds by the loud-speaker 39.

At the end of its stroke, the stud 32 returns into the positionillustrated and switches off the circuit between the blades 34 and 36,which has for its result a stopping of the motor.

Of course, various modifications in shape and in detail arrangements maybe required according to the case and to the application considered andthis may be perforated without widening the scope of the invention, asdefined by the accompanying claims.

What I claim is:

1. An electro-acoustic generator of low frequency signals adapted toproduce through amplification musical sounds, comprising an elasticelongated member, an electric motor, a shaft controlled by said motorand driving the elastic elongated member along a circular path,vibratory members engaging the path of said elongated member and eachadapted to vibrate immediately after they have been shifted out of theirinoperative position by the passage of the elastic elongated member inregistry with them, electric collecting means located in proximity withsaid vibratory members and adapted to transform the vibrations of thelatter into weak electric currents, and means amplifying said currentsand transforming them into musical sounds.

2. An electro-acoustic generator as claimed in claim 1, comprising arigid part radially carried by the shaft and the free outer end of whichcarries the elastic member.

3. An electro-acoustic generator as claimed in claim 1 wherein thevibratory members are constituted by rods of magnetic metal parallelwith the shaft and removably secured in position.

4. An electro-acoustic generator as claimed in claim 1 comprising acircuit energizing the motor, a switch inserted in said circuit, meanscontrolled by said shaft and adapted to control said switch to close thecircuit throughout one revolution of the motor and to deenergize itafter said revolution.

References Cited UNITED STATES PATENTS 2,769,361 11/1956 Kunz 841.25

ARTHUR GAUSS, Primary Examiner.

JAMES BUSCH, Assistant Examiner.

1. AN ELECTRO-ACOUSTIC GENERATOR OF LOW FREQUENCY SIGNALS ADAPTED TOPRODUCE THROUGH AMPLIFICATION MUSICAL SOUNDS, COMPRISING AN ELASTICELONGATED MEMBER, AN ELECTRIC MOTOR, A SHAFT CONTROLLED BY SAID MOTORAND DRIVING THE ELASTIC ELONGATED MEMBER ALONG A CIRCULAR PATH,VIBRATORY MEMBERS ENGAGING THE PATH OF SAID ELONGATED MEMBER AND EACHADAPTED TO VIBRATE IMMEDIATELY AFTER THEY HAVE BEEN SHIFTED OUT OF THEIRINOPERATIVE POSITION BY THE PASSAGE OF THE ELASTIC ELONGATED MEMBER INREGISTRY WITH THEM, ELECTRIC COLLECTING MEANS LOCATED IN PROXIMITY WITHSAID VIBRATORY MEMBERS AND ADAPTED TO TRANSFORM THE VIBRATIONS OF THELATTER INTO WEAK ELECTRIC CURRENTS, AND MEANS AMPLIFYING SAID CURRENTSAND TRANSFORMING THEM INTO MUSICAL SOUNDS.